Corneal surgery to supplement or replace the need for optical aides (e.g., eyeglasses and contact lens) or to treat eye conditions has undergone a steady evolution over the last 50 years or so. Advancements in the field has resulted in even greater attention being given to ways in improving the safety and results of the various techniques involved. This evolution has included the replacement of diamond blade incision techniques such as Radial Keratatomy (RK) and its related procedures of Astigmatic Keratatomy (AK) and Hexagonal Keratotomy (HK) with excimer laser techniques such as Photorefractive Keratectomy (PRK) and Laser Assisted In Situ Keratomileusis (LASIK). The excimer laser can be extremely accurate and removes only small amounts of eye tissue per pulse (e.g., 0.25 microns or 1/4000th of a millimeter). During the resculpturing or other desired effect on the eye, the laser is relied upon to gently "evaporate" tissue through an ablation process on the above noted small amount of eye tissue. In most cases the laser treatment only lasts 20 to 45 seconds depending upon the severity of the refractive error.
As described, for example, in U.S. Pat. No. 5,368,590, in PRK the laser is applied directly to the surface of the cornea, after the thin surface layer of cells or epithelium is removed, to re-shape the cornea to make the resultant curve of the cornea balance the length of the eye in an effort to have the light rays better focus on the retina. Phototherapeutic keratectomy, such as corneal leukoma, pterygium, corneal erosion, and herpetic keratitis surgeries are also described in U.S. Pat. No. 5,368,590 as being suited for laser use. In the PRK procedure, a lid retractor is put into position so as secure the eye lid open so as not to interfere with subsequent treatment steps. The positioning of the retractor leads to the exudation being exuded onto the corneal surface. As described in U.S. Pat. No. 5,368,590 such exudation is eliminated by manually applying a conventional sponge, stick type absorbent, or gauze and/or a drainage tube. The elimination of the exuded liquid is described as being important as the exuded fluid is said to be a source of treatment error due to the liquids disruption of the desired ablation effect on eye tissue. In the noted patent, there is indicated that the prior art techniques fail to maintain a dry eye during sudden releases of large amounts of fluid and describes a large, encompassing corneal sponge designed to provide at least one dry, surgical space. Thus, the '590 reference relies on a peripheral absorption technique to help avoid build up in the treatment area of the eye by drawing the fluid away from that area.
PRK has, however, been generally replaced by the "LASIK" method in which the laser treatment is applied under a corneal flap. This avoids many of the problems often associated with PRK such as the degree of uncomfortableness, correction regression, potential scarring, hazing, unpredictability, etc. which come about, mainly due to the treatment of the regenerative outer layer of the eye during PRK. This is not the case with LASIK as the laser treatment is directed toward reshaping the cornea stroma which does not create the same problems that arise in a PRK procedure. The flap replacement in LASIK also covers the treated area avoiding treatment area exposure which is a main cause of discomfort and potential infection in PRK.
To produce the corneal flap, a portion of the cornea is resected to expose the corneal stroma. U.S. Pat. No. Re. 35,421 to the present inventor, Dr. Luis A. Ruiz, and Sergio Lenchig, which patent is incorporated herein by reference, describes an automated corneal shaper that is well suited for providing the eye resection. The automated corneal shaper provides for a resection in the form of a flap (a hinged resection) for facilitating repositioning or the resection after the exposed surface is subjected to laser treatment. The automatic corneal shaper noted above provides a means for automatically, precisely and safely performing corneal resections for refractive corrections such as hyperopia, myopia, astigmatism, and/or the correction of presbyopia (as described in Dr. Ruiz's U.S. Pat. Nos. 5,533,997 and 5,928,129 each of which is incorporated by reference) and other eye correction techniques where a lamellar resection is desired (e.g., keratomileusis).
In view of the above-noted advantages of LASIK, LASIK surgery has become the standard for refractive surgery, providing excellent results in terms of accuracy, safety, short recovery time and a minimum of post operative symptoms. As described in U.S. Pat. No. 5,755,700 to Kritzinger (which reference is incorporated herein by reference), while a great deal of focus has been on what type of ablation to use in the bed, other areas which warrant attention are safe keratectomy and accurate repositioning of the cap/flap. The above described automatic corneal shaper is directed at the first of the noted concerns. As to the accurate repositioning, the prior art teaches a variety of markers to help in the final repositioning of the flap. An example of one such marker is seen in U.S. Pat. No. 5,752,967 to Kritzinger et al.
As a marker only helps in providing repositioning guidance, it does not provide a solution to the other potential complications associated with flap replacement during LASIK surgery. After the laser portion of LASIK treatment (which often takes place in well under 30 seconds) it is desirable to quickly place the flap or cap back in position from the standpoint of, for example, avoiding prolonged exposure of the corneal stroma and avoiding a large differential between the actual surgical time and the time a patient has to wait before the equipment around the eye can be removed. However, a too hasty replacement can lead to wrinkling or folding of the flap or cap, which, due to the high liquid surface adhesion along the overlapped region, can lead to inadvertent tearing or stretching when attempting to remove folds or wrinkles or in the lifting off of the flap from the corneal stroma for a second attempt at placement.
Also even if the flap is initially positioned properly (e.g., without wrinkles or folds), the conventional drying techniques can introduce wrinkles, folds and non-alignment problems during the course of drying. For instance if the eye is dried by way of a conventional technique such as applying drying air through the end of a conduit with or without an added nozzle end, the force of the applied air (or other gas) stream to the eye can create shifting, wrinkling and folding in the flap. That is, excessive drying can cause wrinkle formation while defective drying can cause inadvertent flap replacement. While the flap can be dried without the assistance of applied air or gas, the time involved for atmospheric drying is undesirable in that it involves a drying time period that is many times the length of time involved for laser application, and requires the patient to remain under the surgical setting for an undesirable long period of time.
There is also know in the art clear plastic "bubble" eye shields with through holes, which shields are used post operatively to protect the eye from trauma. An illustration of one such bubble shield is found on page 121 of "Surgery For Hyperopia and Presbyopia" by Neal Sher, MD, FACS. This device is far removed from an eye drying device.